Methods for pre-treatment of lignocellulose by adding alkaline or acidic reagent(s) during densification thereof and for biotransformation thereof

Abstract

Disclosed are methods for the pre-treatment of lignocellulose by adding an alkali or acid reagent(s) during the densification thereof, and for the biotransformation thereof. In the method, an alkali reagent(s) or acid reagent(s) is added to a lignocellulosic raw material for a densification pre-treatment to form an alkali- or acid-containing densified lignocellulose with a compressed compact shape, thereby achieving the pre-treatment. The acid or alkali in the pre-treated lignocellulose can further pre-treat the lignocellulosic raw material in a mild manner during the subsequent transportation and storage processes. If a subsequent pre-treatment is needed, then the severity thereof is reduced substantially; in addition, the uniform mixing of the acid or alkali with the lignocellulose and a large density of the raw material promote a high efficiency and a high loading capacity of the subsequent pre-treatment of the densified lignocellulose. The method is simple and efficient. The resulting lignocellulosic raw material has a large density, will not easily degrade or rot due to the inclusion of an acid or alkali, which is conducive to transportation and storage, and a high equipment utilization rate during the subsequent treatment is achieved.

The invention claimed is: 
     
       1. A method for pretreating a lignocellulose with an alkaline reagent(s) or an acidic reagent(s) during densification, comprising:
 adding the alkaline reagent(s) or acidic reagent(s) during the densification of a lignocellulose raw material to obtain an acid- or base-containing densified lignocellulose with a density of 200-1500 kg/m 3  and a moisture content of 31.3% or less. 
 
     
     
       2. A method for bio-transforming an acid- or base-containing densified lignocellulose, comprising:
 adding the alkaline reagent(s) or acidic reagent(s) during the densification of a lignocellulose raw material 
 to obtain an acid- or base-containing densified lignocellulose with a density of 200-1500 kg/m 3  and a moisture content of 31.3% or less, which can be directly bio-transformed or further selectively pretreated for a subsequent bio-transformation. 
 
     
     
       3. The method of  claim 1 , characterized in that:
 the lignocellulose is selected from one or more of the following: wheat straw, corn stover, rice straw, sorghum stover, soybean stover, recycled wood pulp fiber, wood chips, softwood, hardwood, aquatic weed, algae, animal feces and combinations thereof. 
 
     
     
       4. The method of  claim 1 , characterized in that:
 the alkaline reagent(s) is selected from one or more of the following: sodium hydroxide, calcium hydroxide, potassium hydroxide, sodium sulphite, sodium bisulfite, sodium acetate, sodium carbonate, sodium bicarbonate, sodium sulfate, ethylenediamine, triethylamine, ammonia water, liquid ammonia, calcium oxide, sodium oxide, and combinations thereof. 
 
     
     
       5. The method of  claim 1 , characterized in that:
 the acidic reagent(s) is selected from one or more of the following: sulfuric acid, nitric acid, nitrous acid, hydrochloric acid, phosphoric acid, sulphurous acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, oxalic acid, formic acid, acetic acid, propionic acid, benzoic acid, phenylacetic acid, benzenesulfonic acid, oxalic acid, succinic acid, carbon dioxide, sulfur dioxide, sodium bisulfate, sodium bisulfite, and combinations thereof. 
 
     
     
       6. The method of  claim 1 , characterized in that:
 the dosage of the alkaline reagent(s) or acidic reagent(s) is in the range of 0.5%˜30.0% by weight of the lignocellulose. 
 
     
     
       7. The method of  claim 1 , characterized in that:
 the alkaline reagent(s) or acidic reagent(s) can be directly added in the form of pure base reagent(s) or acidic reagent(s), or in the form of an aqueous solution of the base or acidic reagent(s). 
 
     
     
       8. The method of  claim 1 , characterized in that:
 the alkaline reagent(s) or acidic reagent(s) can be directly poured or added, sprayed, brought in via steam, or sprayed as an alkaline or acidic gas, such that the alkaline or acidic reagent(s) can be fully mixed with the lignocellulose for performing a lignocellulose densification treatment; or 
 during the densification, the alkaline reagent(s) or acidic reagent(s) and the lignocellulose are added to a densification equipment to produce a densified lignocellulose with a dense shape. 
 
     
     
       9. The method of  claim 2 , characterized in that:
 the acid- or base-containing densified lignocellulose without further pretreatment can be subjected to biotransformation immediately or after standing for a certain period of time. 
 
     
     
       10. The method of  claim 2 , characterized in that:
 the acid- or base-containing densified lignocellulose can be further selectively pretreated for the subsequent biotransformation, and the further selective pretreatment of densified lignocellulose is selected from the following: spraying water on the lignocellulose, steaming, soaking, sun exposure, freezing, high temperature treatment, cooking in water, high temperature sterilization, microwave, ultrasonic treatment, steam explosion, hot water pretreatment, steam pretreatment, dilute acid pretreatment, weak acid pretreatment, oxidative acid pretreatment, mixed acid pretreatment, dilute alkaline pretreatment, weak alkaline pretreatment, ammonia pretreatment, oxidative alkaline pretreatment, mixed alkaline pretreatment, or organic solvent pretreatment. 
 
     
     
       11. The method of  claim 1 , characterized in that:
 the densified lignocellulose has a rod shape with a diameter of 1 mm-30 cm; a granule shape with a diameter of 0.1 cm-50 cm; 
 a block shape with a length of 0.1 cm-200 cm, a width of 0.1 cm-200 cm, and a height of 0.1 cm-200 cm; or a pellet shape with a diameter of 0.1 cm-50 cm and a thickness of 0.01 cm-20 cm. 
 
     
     
       12. The method of  claim 2 , characterized in that:
 the biological transformation comprises: 
 an enzymatic reaction comprising adding enzymes or fermentation in a pretreatment substrate, wherein the enzyme is selected from one or more of cellulase, hemicellulase, pectinase, xylanase, amylase and saccharification enzyme, and/or 
 a microbial transformation which is a microorganism fermentation comprising adding a fermenting microorganism into a pretreatment substrate or enzymatic hydrolysate, and the fermenting microorganism is selected from one or more of yeast, bacteria, and mold. 
 
     
     
       13. The method of  claim 2 , characterized in that:
 the biotransformation has a product comprising biofuels, commodity chemicals, fine chemicals, animal feeds, food additives or medicines. 
 
     
     
       14. The method of  claim 13 , characterized in that:
 the product is selected from ethanol, butanol, acetone, acetic acid, lactic acid, aliphatic hydrocarbon, lipids, proteins, amino acids, enzymes, antibiotics, vitamins, antibodies, and methane. 
 
     
     
       15. The method of  claim 2 , characterized in that:
 the lignocellulose is selected from one or more of the following: wheat straw, corn stover, rice straw, sorghum stover, soybean stover, recycled wood pulp fiber, wood chips, softwood, hardwood, aquatic weed, algae, animal feces and combinations thereof. 
 
     
     
       16. The method of  claim 2 , characterized in that:
 the alkaline reagent(s) is selected from one or more of the following: sodium hydroxide, calcium hydroxide, potassium hydroxide, sodium sulphite, sodium bisulfate, sodium acetate, sodium carbonate, sodium bicarbonate, sodium sulfate, ethylenediamine, triethylamine, ammonia water, liquid ammonia, calcium oxide, sodium oxide, and combinations thereof. 
 
     
     
       17. The method of  claim 2 , characterized in that:
 the acidic reagent(s) is selected from one or more of the following: sulfuric acid, nitric acid, nitrous acid, hydrochloric acid, phosphoric acid, sulphurous acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, oxalic acid, formic acid, acetic acid, propionic acid, benzoic acid, phenylacetic acid, benzenesulfonic acid, oxalic acid, succinic acid, carbon dioxide, sulfur dioxide, sodium bisulfate, sodium bisulfate, and combinations thereof. 
 
     
     
       18. The method of  claim 2 , characterized in that:
 the dosage of the alkaline reagent(s) or acidic reagent(s) is in the range of 0.5%˜30.0% by weight of the lignocellulose. 
 
     
     
       19. The method of  claim 2 , characterized in that:
 the alkaline reagent(s) or acidic reagent(s) can be directly added in the form of pure base reagent(s) or acidic reagent(s), or in the form of an aqueous solution of the base or acidic reagent(s). 
 
     
     
       20. The method of  claim 2 , characterized in that:
 the alkaline reagent(s) or acidic reagent(s) can be directly poured or added, sprayed, brought in via steam, or sprayed as an alkaline or acidic gas, such that the alkaline or acidic reagent(s) can be fully mixed with the lignocellulose for performing a lignocellulose densification treatment; or 
 during the densification, the alkaline reagent(s) or acidic reagents) and the lignocellulose are added to a densification equipment to produce a densified lignocellulose with a dense shape.